AUGUSTA, Maine (AP) — It can be hard to keep smiles healthy in rural areas, where dentists are few and far between and residents often are poor and lack dental coverage. Efforts to remedy the problem have produced varying degrees of success.

The biggest obstacle? Dentists.

Dozens of countries, such as New Zealand, use “dental therapists” — a step below a dentist, similar to a physician’s assistant or a nurse practitioner — to bring basic dental care to remote areas, often tribal reservations. But in the U.S., dentists and their powerful lobby have battled legislatures for years on the drive to allow therapists to practice.

Therapists can fill teeth, attach temporary crowns, and extract loose or diseased teeth, leaving more complicated procedures like root canals and reconstruction to dentists. But many dentists argue therapists lack the education and experience needed even to pull teeth.

“It can kill you if you’re not in the right hands,” said Peter Larrabee, a retired dentist who teaches at the University of New England. “It doesn’t happen very often, but it happens enough.”

Dental therapists currently practice in only four states: on certain reservations and schools in Oregon through a pilot program; on reservations in Washington and Alaska; and for over 10 years in Minnesota, where they must work under the supervision of a dentist.

The tide is starting to turn, though.

Since December, Nevada, Connecticut, Michigan and New Mexico have passed laws authorizing dental therapists. Arizona passed a similar law last year, and governors in Idaho and Montana this spring signed laws allowing dental therapists on reservations.

Maine and Vermont have also passed such laws. And the Connecticut and Massachusetts chapters of the American Dental Association, the nation’s largest dental lobby, supported legislation in those states once it satisfied their concerns about safety. The Massachusetts proposal, not yet law, would require therapists to attain a master’s degree and temporarily work under a dentist’s supervision.

But the states looking to allow therapists must also train them. Only two states, Alaska and Minnesota, have educational programs. Minnesota’s program is the only one offering master’s degrees, a level of education that satisfies many opponents but is also expensive.

Some dental therapists start out as hygienists, who generally hold a two-year degree. Some advocates of dental therapists argue they should need only the same level of education as a hygienist — a notion that horrifies many opponents.

Some lawmakers in Maine, which will require therapists to get a master’s from an accredited program, are optimistic about Vermont’s efforts to set up a dental therapy program with distance-learning options. It’s proposed for launch in fall 2021 at Vermont Technical College with the help of a $400,000 federal grant.

Christy Jo Fogarty, a Minnesota dental therapist, said the organization she works for saves $40,000 to $50,000 a year by having her on staff instead of an additional dentist — and that’s not including the five other therapists.

According to state law, at least half of Fogarty’s patients must be on governmental assistance or otherwise qualify as “underserved.”

“Why would you ever want to withhold these services from someone who was in need of it?” she said.

Ebyn Moss, 49, of Troy, Maine, has had four teeth pulled, a bridge installed, a root canal, two dental implants and seven cavities filled at a cost of $6,300 since 2017, and expects to shell out another $5,000 in the next year — a bill Moss is paying off with a 19% interest credit card and $16,000 in annual income.

“That’s the cost of choosing to have teeth,” Moss said.

Now, Moss gets treated at a dental school in Portland — a two-hour drive for appointments that can last 3 1/2 hours. A dental therapist nearby would have made preventive care easier in the first place, Moss said.

The ADA and its state chapters report spending over $3 million a year on lobbying overall, according to data from the National Institute on Money in Politics. The Maine chapter paid nearly $12,000 — a relatively hefty sum in a small state — to fight the 2014 law that spring.

Legislation failed in North Dakota and Florida this spring. Bills are pending in Kansas, Massachusetts and Wisconsin, as well as Washington, where therapists could be authorized to practice outside reservations.

“Available data have yet to demonstrate that creating new midlevel workforce models significantly reduce rates of tooth decay or lower patient costs,” ADA President Jeffrey Cole said in an email.